Thursday, February 07, 2008

Solenoid Lock -- Hardware

The bulk of the hardware construction is covered in the wireless lock writeup. I'll only cover the additional steps needed below:

New Parts:
> Square dowel that will fit into the door knob.
> Trim-pot(See electronics section)

New tools:
> Needle nosed pliers
> Hot glue gun
> Sanding drum for Dremel
  1. The door handle must be modified, since it only allows 90 degrees of freedom, and a standard trim pot is usually just shy of a full 180. It's 'simply' bending anything that hits the side upwards till it doesn't hit. This includes 2 spring ends and 2 metal tabs. I used normal needle nosed pliers and a flat tip screwdriver and got it with not too much effort. Pic below:
  2. Next a dowel needs to be cut to fit to the proper length. Should be enough to mount the trimpot inside the metal and then have it be snug against There is a picture further down when I discuss gluing that shows this better. Below is a picture of the dowel in the door(I was retarded and had to shape a circular one to work), it's sticking out a little just so I could feel how tight it was in the handle:
  3. This is the most difficult part IMO, since it's prone to screwing up, and helps if done correctly. The end of the dowel needs to be carved to fit into the trim pot. For example if your trim pot has a straight slit for a flat tip screwdriver then you need to carve something roughly resembling a flat tip head on the dowel. I used a Dremel sanding tool to to this. In the end you should be able to control the potentiometer with the dowel.
  4. Next glue the Dowel onto the trimpot, you'll have to take off the door handle assembly entirely for this to get it straight. I originally tried epoxy but it didn't stick to the trimpot plastic so I went with hot glue which worked well. Picture of it 'clamped' up below:
  5. Solder up wiring to the trim pot for later use since it will be hard to get to after it's in place.
  6. Finally put it all back on the door. You can no longer put in the latch(The middle section) since it also hinders rotation. The dowel should slide into the handle, and turning the handle should now turn the trim pot.

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